'\" et
.TH SIGISMEMBER "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.

.SH NAME
sigismember
\(em test for a signal in a signal set
.SH SYNOPSIS
.LP
.nf
#include <signal.h>
.P
int sigismember(const sigset_t *\fIset\fP, int \fIsigno\fP);
.fi
.SH DESCRIPTION
The
\fIsigismember\fR()
function shall test whether the signal specified by
.IR signo
is a member of the set pointed to by
.IR set .
.P
Applications should call either
\fIsigemptyset\fR()
or
\fIsigfillset\fR()
at least once for each object of type
.BR sigset_t
prior to any other use of that object. If such an object is not
initialized in this way, but is nonetheless supplied as an argument to
any of
\fIpthread_sigmask\fR(),
\fIsigaction\fR(),
\fIsigaddset\fR(),
\fIsigdelset\fR(),
\fIsigismember\fR(),
\fIsigpending\fR(),
\fIsigprocmask\fR(),
\fIsigsuspend\fR(),
\fIsigtimedwait\fR(),
\fIsigwait\fR(),
or
\fIsigwaitinfo\fR(),
the results are undefined.
.SH "RETURN VALUE"
Upon successful completion,
\fIsigismember\fR()
shall return 1 if the specified signal is a member of the specified set,
or 0 if it is not. Otherwise, it shall return \(mi1 and set
.IR errno
to indicate the error.
.SH ERRORS
The
\fIsigismember\fR()
function may fail if:
.TP
.BR EINVAL
The
.IR signo
argument is not a valid signal number, or is an unsupported signal
number.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "Section 2.4" ", " "Signal Concepts",
.IR "\fIpthread_sigmask\fR\^(\|)",
.IR "\fIsigaction\fR\^(\|)",
.IR "\fIsigaddset\fR\^(\|)",
.IR "\fIsigdelset\fR\^(\|)",
.IR "\fIsigfillset\fR\^(\|)",
.IR "\fIsigemptyset\fR\^(\|)",
.IR "\fIsigpending\fR\^(\|)",
.IR "\fIsigsuspend\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2008,
.IR "\fB<signal.h>\fP"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.unix.org/online.html .

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